how to click one treenode then something happen?

// Handle the After_Select event.
    private void TreeView1_AfterSelect(System.Object sender,
        System.Windows.Forms.TreeViewEventArgs e)
    {
        // Vary the response depending on which TreeViewAction
        // triggered the event.
        switch((e.Action))
        {
            case TreeViewAction.ByKeyboard:
                MessageBox.Show("You like the keyboard!");
                break;
            case TreeViewAction.ByMouse:
                MessageBox.Show("You like the mouse!");
                break;
        }
    }

void treeView1_NodeMouseClick(object sender,
    TreeNodeMouseClickEventArgs e)
{
    textBox1.Text = e.Node.Text;
}